Thanks for writing to us.
Brahmalin ghrita can be used to increase the memory of your son but whether it will help in relaxing his tension during the exams is doubtful.
Regarding its dosage and side effects it is best to consult an ayurveda specialist
who will give you proper directions after assessing the requirement.
I hope this information has been both informative and helpful for you.
Dr. Rakhi Tayal